Solve the problem. Round your answer to two decimal places.
-The distance it takes to stop a car varies directly as the square of the speed of the car. If it takes 112 feet for a car traveling at 40 miles per hour to stop, what distance is required for a speed of 45 miles per hour?
A) 154.05 ft
B) 141.75 ft
C) 121.5 ft
D) 142.09 ft

Question

Quizplus · Accepted Answer

The stopping distance varies directly with the square of the speed, so we use the formula $ d = k \cdot s^2 $. First, find $ k $ using the given data: $ 112 = k \cdot 40^2 $. Solving for $ k $, we get $ k = \frac{112}{1600} = 0.07 $. For 45 mph, $ d = 0.07 \cdot 45^2 = 141.75 $ feet.

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